These studies will explore treatment strategies for chronic Lyme disease and will determine the safety and efficacy of ceftriaxone and doxycycline in the treatment of patients with seropositive chronic Lyme disease. The objectives of this study are to determine whether: a. intensive antibiotic treatment benefits seropositive patients with CLD; b. evidence of persistent infection with Borrelia burgdorferi can be found inpatients with CLD; c. evidence of co-infection with other microorganisms can be found in patients with CLD; d. specific clinical or laboratory parameters improve in patients who receive antibiotic therapy compared to patients who receive placebo and; e. specific parameters are predictive of a response to therapy should it be observed.